Answer:
Answer D: f(-2) = 2
Step-by-step explanation:
To evaluate f(-2) we need to find what is the y-value that the graph shows for the x-value "-2".
To find such, we look for the value x = -2 on the horizontal (x) axis (located two units to the left of the origin of coordinates (0,0)), and from there, we investigate at what y-value (value on the vertical y-axis) a line that follows the vertical grid passing through x = -2, intercepts the graph of the function.
That is pictured with a red dot in the attached image. Notice that the y-value at which such intersection occurs is y = 2.
Therefore f(-2) = 2
The area of a circle is given by

We can solve this equation for r: divide both sides by pi:

Consider the (positive) square root of both sides:

So, in your case, we have

Answer: r = 3
Step-by-step explanation:
Step 1: Cross-multiply.
2r = 12/18
(2)*(18)=12*r
36=12r
Step 2: Flip the equation.
12r=36
Step 3: Divide both sides by 12.
12r/12 = 36/12
r = 3